I need a rotorhead to explain this one

**Kyobanim** · 05-17-2007, 12:47

I don't think this is a model and even if it is, it still defys the laws that make choppers fly. What am I missing?

http://spluch.blogspot.com/2007/05/h...opter-fly.html

**The Reaper** · 05-17-2007, 13:01

Russian Hind D.

Not an aviator, but taking a guess. It is coming down, but the tail rotor keeps it from spinning much under the main rotor.

If he does not re-engage the main rotor under engine power, he will need to do an autorotation prior to impact, or it will be messy.

TR

**Pete** · 05-17-2007, 13:16

The second clip makes it look like it was a demo at an air show.

I'll bet he wasn't maxed out on weight.

**Bill Harsey** · 05-17-2007, 13:22

Based on country of manufacture and origin, vodka may be involved.

Yes that looks like an airshow crowd.

**Roguish Lawyer** · 05-17-2007, 13:54

Did you read the answer below the video, Kyo?

**Kyobanim** · 05-17-2007, 15:17

I read what someone posted as the reason it stayed in flight but I didn't buy it. From what I understand, the rotor blades need to be turning to provide lift and act like a wing. That guy was doing manuevers with a static rotor. Maybe I'm wrong, but I think it's a good piece of film editing. The sound trac makes me think this also.

PSM · 05-17-2007, 15:34

Besides whatever lift is provided by the “braked” main rotor, the stub wings do provide lift as well.

Pat

**Team Sergeant** · 05-17-2007, 15:39

It's a model on a string......

Turn off the sound and watch it again.....

TS

JGarcia · 05-17-2007, 16:29

Ditto, what TS said.

Even if the blades were providing lift, and the turbine engines providing thrust, the rotor blades would be "coning" lifting upward from their roots, as if the ACFT were being held up by its wingtips, the weight of the ACFT pulling down heavily at its CG. To maintain level or controlled flight the wing would have to provide lift on both sides of the ACFT. Since rotor blades "rotate" and a wing only provides lift when air is flowing over the leading edge, and in the video the main rotors are stationary, yet the ACFT is moving forward, only the blade on the left side of the ACFT would be providing any lift. The left side of the ACFT would rotate up and over, instead of maintaining level or controlled flight.

Once upon a time when I was a shiny new private I got to patrol the Czech/FRG border. I watched a HIND, trail a Cobra along the border for a bit. When the HIND flew, it spit out copious amounts of black exhaust smoke, especially when the pilot would dump the collective to make a turn. No exhaust smoke in this video, from my limited experience, this is a neat video trick.

If these engines were doing all the work, all kinds of exhaust would be coming out, in order to provide enough thrust for the stubby winglets, straining as if trying to squeeze out a turd that has no intention of moving along along nicely.

**Ambush Master** · 05-17-2007, 20:38

I think that I just broke the code!!!!

Look at the Tail Rotor. See how it appears to be turning slowly, the tail rotor turns much faster than the main so while it appears to still be turning the main is stopped!! They have synced the film speed/capture rate if digital, to make the Main Rotor appear to stand still. Listen to the sound, you can hear the "normal" sounds associated with a fling-wing!!!

Also, in the turns, you can see the blades flex in all of the proper areas for the maneuver.

But,................ what do I know!!

Later
Martin

PSM · 05-17-2007, 20:55

Quote:

Originally Posted by Ambush Master

I think that I just broke the code!!!!

Look at the Tail Rotor. See how it appears to be turning slowly, the tail rotor turns much faster than the main so while it appears to still be turning the main is stopped!! They have synced the film speed/capture rate if digital, to make the Main Rotor appear to stand still. Listen to the sound, you can hear the "normal" sounds associated with a fling-wing!!!

Also, in the turns, you can see the blades flex in all of the proper areas for the maneuver.

But,................ what do I know!!

Later
Martin

I considered that also, but then what's the purpose of the demonstration? He was only doing what every wing-slinger can do.

Pat

**Ambush Master** · 05-17-2007, 21:02

Quote:

Originally Posted by PSM

I considered that also, but then what's the purpose of the demonstration? He was only doing what every wing-slinger can do.

Pat

Exactly!!! The Helo was not doing anything "Special", the Film Maker was, just for the type of exposure that it is getting on the net!!!! You may have considered it, but you didn't put it together!!

PSM · 05-17-2007, 21:26

Quote:

Originally Posted by Ambush Master

Exactly!!! The Helo was not doing anything "Special", the Film Maker was, just for the type of exposure that it is getting on the net!!!! You may have considered it, but you didn't put it together!!

It's hard to tell who, and how large, the audience is in the second video, so even simple maneuvers might be impressive to them.

I agree that it may be a hoax because video of the takeoff and transition to non-rotary flight would be more impressive video. Then again, the stub wings do provide up to 30% of the lift.

Pat

**Ambush Master** · 05-17-2007, 21:31

Quote:

Originally Posted by PSM

Then again, the stub wings do provide up to 30% of the lift.
Pat

Only when HAULING ASS in a forward direction!!! They would provide Zero Lift throughout the flight profiles shown!!

Later
Martin

NSDQ · 05-17-2007, 21:47

Quote:

Originally Posted by Team Sergeant

It's a model on a string......

TS

I am not sure what & how they did this, but it was not a full scale "flyable" HIND.

Facts supporting the idea of it being a model;
1. Unlike on a flyable life size acft or model RC acft the tail rotor is mechanically linked to the main rotor thru a series of driveshafts, couplers, flexpacks, thru the transmission/s drivegear. The only way that the M/R & T/R can turn independently is if there has been a major failure in one of these components, i.e driveshaft sheared in half, gear teeth sheared off inside the xmsn, etc. if you notice in the videos the T/R continues to rotate, while the M/R just moves a little. Now, even though we know because of reduction gearing, the T/R will spin faster then the M/R it will still spin at a fixed ratio, whether it be 10:1, 17:1 or whatever the manufacturing desined it to be. If you will focus on 1 of the 5 M/R blades you will see they never get out of a specific quadrant, much less make 1 full rotation. At 1 point you can even see the M/R going opposite direction of normal operation.
2. The sound bite is that of a smaller helicopter, I am not sure which. A HIND has a more throatier, basser signature, more along the lines of our HH-53's
3. Model's (non RC) do not have a linked M/R & T/R, therefore you can spin them independently.

Facts supporting it not being a real HIND;
1. The main rotor is not turning!
2. Think of an autorotation of a helicopter similiar to that of a parachute. It is a (somewhat) controlled descent. You are not going to create enough lift with your chute to fly with it, like to avoid a tree, bolder, water, etc. There is not enough lift being created by a virtually staionary blade to keep the HIND in the air. It would be like jumping with a GI Joe chute verses a real chute. the GI Joe chute does have lift but not enough displacement to mass to support a full sized man. Neither can the 1 blade that does have the correct angle to create lift sustain its own weight much less that of a full size ACFT. We are not talking about having thermals & artificial means of increasing airflow over your wing. With that being said a real HIND whould have balled in like a rock.

There is much more that can be said about why this is a staged & doctored video, but I will stop for now.
I will say, that they did think enough to make the whine of the engines in line with the postion of the ACFT as it was flying and the part where it was staged in front of the airshow was well done.

NSDQ